Radio frequency identification (RFID) systems generally include at least one reader and a plurality of transponders which are typically termed RFID credentials. One common type of RFID credential comprises a passive radio frequency communication device embedded in a portable substrate, which is in the form of a plastic identification card and is termed an RFID card. The RFID card is carried by a person to be identified or otherwise characterized by a reader of an RFID system. The passive RFID card is dependent on the reader for its power. The reader “excites” or powers up the RFID card by transmitting excitation signals of a given frequency into the space surrounding the reader, which are received by the RFID card and provide the operating power for the circuitry of the recipient RFID card.
Communication between the reader and the RFID card is enabled by cooperative resonant circuits which are provided in each reader and RFID card. Each resonant circuit includes an inductor, typically in the form of an antenna, which magnetically couples to the inductor of the other resonant circuit through mutual inductance.
Communication is initiated when an RFID card is proximally positioned relative to the reader. The reader has a power supply which conveys a current to the reader resonant circuit causing the reader antenna to produce an excitation signal in the form of an electromagnetic field. The excitation signal couples to the antenna of the proximally-positioned RFID card through mutual inductance and the excitation signal powers and clocks the card circuitry initiating operation of the RFID card.
Card operation comprises generation of a response signal at a specified frequency and transmission of the response signal back to the reader. In particular, the card resonant circuit receives a current in response to the excitation signal which causes the card antenna to produce a response signal in the form of an electromagnetic field. The response signal couples to the reader antenna through mutual inductance in substantially the same manner as described above with respect to coupling of the excitation signal to the card antenna. The RFID card typically employs frequency or amplitude modulation of the response signal to encode data stored in the memory of the card circuitry into the response signal. When the response signal couples to the reader antenna, a corresponding current is induced in the reader antenna at the specified frequency. The reader processes the induced current to read the data encoded in the response signal from the RFID card.
RFID cards are commonly used for personal identification or security access applications during normal workday activities. For example, an individual may require his or her own personal RFID card to gain access into a secured area such as an office building, an elevator floor, an office suite, or a parking complex. To gain access to the secured area, the individual simply places the personal RFID card near a reader positioned at the entrance to the secured area so that the reader, which may be networked to a remote host computer, can identify the individual and authorize access to the secured area if appropriate.
It is apparent that in many cases it is necessary for an individual to make frequent use of a personal RFID card during the normal course of a work day. Accordingly, it is desirable for an individual to carry a personal RFID card on his or her person at all times during the work day. Although the RFID card is sized to easily fit within a purse, wallet, clothing pocket, briefcase, or other similar conventional mobile storage location, it is often inconvenient and cumbersome for the card holder to recall the specific mobile storage location where the RFID card is being stored at any given moment and to retrieve the RFID card from that location each time the card holder is required to present the RFID card. A more convenient and accessible means for a card holder to carry an RFID card on his or her person is desirable.
One specialized device a card holder can use to carry a personal RFID card on his or her person, which is both convenient and accessible, is termed a badge reel. Conventional badge reels are widely available, for example, at Sogedex, Parc d'activitès de Pissaloup4, rue Edouard Branly, Bat. Hermès 1, 78190 Trappes, FRANCE (website: www.sogedex.fr) or Baudville, Inc., 5380 52nd Street SE, Grand Rapids, Mich. 49512, USA (website: shop.baudville.com).
A badge reel is essentially a tether for a badge (e.g., card) such as an RFID card. The badge reel consists of a line having one end attached to a spool, which has a mechanical biasing force applied to it to maintain the line wound on the spool. The free end of the line is attached to the RFID card. The badge reel is also provided with a clip for attachment to the outer clothing of a card holder. When the card holder desires to use the RFID card, the card holder simply grasps the RFID card, which is positioned proximal to the body, and pulls the RFID card away from the body to play out the line from the spool. When the line is unwound from the spool, the card holder is able to position the RFID card away from the body where the RFID card can easily be presented to a card reader without requiring the card holder to stand in a specific position. Once the card reader has read the RFID card, the card holder releases the RFID card from grasp. The mechanical biasing force of the spool reels the line back in and the RFID card returns to an unobtrusive position proximal to the body of the card holder.
Because RFID cards typically contain private and/or confidential information, there is a concern that the information can be inadvertently and undesirably accessed by any card reader which happens to be within the path of the card holder when the card holder is moving about during normal workday activities while carrying his or her personal RFID card. To overcome this concern, a means is needed for rendering the RFID card inoperable when the card holder has no intent or need to use the RFID card, yet which does not diminish the ready accessability of the RFID card when needed by the card holder.
Accordingly, it is generally an object of the present invention to provide an RFID card retention assembly which prevents information contained in an RFID card from being inadvertently read by a proximal card reader when the card holder does not intend to use the RFID card. It is generally another object of the present invention to provide such an RFID card retention assembly which maintains the RFID card readily accessible to the card holder at all times should the card holder desire to use the RFID card. It is still another object of the present invention to provide such an RFID card retention assembly which shields the RFID card from view when not in use. These objects and others are accomplished in accordance with the invention described hereafter.